Fluid pumping



Mam 1, 1932. E, A, wem/ER 1,847,286

FLUID PUMPING Filed July 20, 1929 by Tim/1:@ am W Aftfys.

Patented Mar. 1,A 1932 EASTMAN A'. WEAVER, or wINoHEsTEa, MASSACHUSETTS, Assranoar uEsNE AssIemSrENTs', To sTATon REFRIGERATION, INC., A CORPORATION or DmwAnE Twin nimma 'Appmation mea July 2o, 1929. iserm No. 379,344.'

This invention relates'I toi an improved apparatus and method for feeding fluid from a region of low pressure to a warmer reg1on lat higher pressure concomitant'ly with the evaporation vof the fluid. I

The present invention is particularly de?y signed to lprovide fluid feed means which is adapted to a Wide variety of use and which effects the automatic circulation of fluid from a low pressure region to a region' at a higher temperature and pressure without thel -necessity of; moving parts, auxiliary liquid circuits to pump the fluid, .or the like. Accordingly means of this character forin'V ducing fluid flow is particularly useful in apparatus Which`shou-ld require a minimum of expert mechanical attention, replacement of parts, etc. For example, in the field of household refrigeration it is highly desirable to avoid the use ofmechanical pumps or the like with the accompanying vibration, noise, Wear, and` possible mechanical failure, and

in apparatus of this character it'is desirable to return a circulating fluid to the boiler, which preferably is maintained at a comparatively high pressure. The present invention provides means which may be advantageously used in conjunction with a refrigerating system of the absorption type to return the strong solution of refrigerant and absorbent liquids to the generator a ainst a comparatively high pressure in the atter. Fluid feed apparatus of this character may also be advantageously-used in conjunction with refrigerating apparatus of the character disclosedinmycopendingapplication Serial No. 7 33,699, filed August 23, 1924, patented June 3, 1930, :f1: 1,761,551 permitting suchl a system to operate .with greater pressure differentialsy and accordingly higher efficiency and/or permitting the systernto be more compact than otherwise possible. V

WhileI have particularly referred to the. advantages and -utility of the fluid feeding apparatus in conjunction` with refrigerating systems, it is obvious thatthis is4 but a typicalapplication of the invention and that the same may be employed ina wide variety of env1ronments Where it is desired to direct fiuidt from a low pressure region to ahigh pressurev region where it is vaporized. In order to ermit the automatic pumping of fluid in tiis manner'I preferably utilizea Wallof porous material between the regions at different pressures, supplying the fluid in its liquid phase tothe low pressure sidefof the wall which is provided with numerous capillary passages that are adapted to feed the fluid to the high pressure portion thereof. Preferably the circulating fluid and the porous material are so chosen that ,the fluid in its liquid phase Will'readily wet the material, having a suitable surface attraction in relation to the chosen capillary material sothat its` surface forms a very small angle of contact With the walls of the capillary passages, the diameter of which should be inversely-proportioned to the pressure against which it is desired to pump. When the cir-, culating fluidand capillary material are thus chosen, the liquid will continue to flow toward the high pressure ends of the capillary passagesy where it is vaporized, despite f a considerable difference between the pressures at opposite ends of the passages; for example, fluid m'ay be circulated agalnst ressure differences of well above one atmosp 1ere.

The employment of a'liquid having a very small angle of'contact with the capillary passage permits the evaporation of the same due tothe heat supplied at the high pressure side of the porous wall and the automatic replenishment of the evaporated liquid from the low pressure side of the wall so that the concave surface of the minute liquid column does not retreat under the higher pressure to which it is subjected; in other words, as the pressure increases due to the evaporation of the liquid in response to heat, the surface of Jthe liquid at the end of a capillary passage becomes stretched while the advanced edges'thereof in contact with the wall retain substantially the same position.

In order to permit the effective heating o f the li uid in order to cause ra id evaporation o the same, I preferably' ocate a heat conductive non-volatile material of a type which will'not wet the walls of the capillary I passages in contact with the high preure side of the porous Wall. l Thus, forexample,

loo

unglaaed porcelain orearthenware may be #13761762 'It-is evident however,

employed inconjunction with many'ci'rculatthat means of 'this character ma'y o be eming h uids, and mercury or lead may be employedwith comparable advantage for a wide loy as the heat. cbnductive, non-.volatilevariety-'of purposes and in widelydiffercnt 'quid in contact with the,V high pressure side' mstallationjs.

of the wa1l,it being understood that the va- The accompanying4 `drawings illustrate a 1 porized circulating liquid bubbles through'` refrigerating system whichlmay em loy a i outlet uct.

this li uid `and is vented through a .suitable .propelle'n't' liquid such as a hy'drocar n of In the preferred practical application'of my 'invention I supp y the circulating liquid whilethe refrigerant may be a suitable more to asuitable chamber within which aoiler is volatile liquidl such as water. A stem of located, one end of the chamber referably this character comprises'a boiler 1 in which A mined in relation toits' area and thecapillary trans to the lor purposes of convenientillustrati'on I' have shown myA improved -ili'iid pumping-or 19;

the'boiler 'f a refrigerating systemof the return the cndensed l A'cation referred to above and the copending forming onef er o ' transfer relation to the contents of the chamthe duct 20 generated b the boiler preferably passes out have illustrate one t` ical installation `of Fi 2 isa central section through the boiler i whic 4forms part of the apparatus shownin "159,343, filed January 6,

end ofthe boiler wal and the tl1`e propellant is vaporiz'edand fromwhich Vremain t. the boiler being formed by .a it rises through the pipe 3 to the aspirator cup Aof porous material with its edges heldl nozzle 4 where there is a large increase in .veinpressure-tight relation withthel common locity and decrease in the fessure of the .wall of the boiler andchamber. Preferably propellent vapor" stream. iquid refrigerheat S Sllplied t0 the intrim* 0f the boiler ant is containedjn-the cooler 5 and refriger.

that the eating factoris not in direct heat 'ant v'porjs drawn from this ljgud through being entraiiied in t' e. propellant ber which surroundthe boiler: Accordingly stream 'which glves Jup jtskinetic energy the incoming liquid may remain at atempera in the pumpin .off thg refrigerant. ava' r ture at which evaporation of the saine does` The mixture o refriv rantv and lpi-ope ent not readil occuruntil it passes through the vapors passes t0 t e inclined-funnel 6 wall of t e porous cup. The latter` 3S a1'- rwhich-is provide with cooling means '21 in ranged t0 PI'OVld im ample area., i. `e. a large order to. cause. condensation of the major the petroleum family', `for example, of thel characterof heavy kerosene'or mineral oil, 75

number of capillaryjpassages, so .that an ade# portionof the propellant at a comparatively 41118150 amoflt fllid maysow'hloughthef hightemperature and the drainage of the $8me, th6 thlcklleSS tof the c upbelngso detelsametowardthe lower 'end'of the funnel.

It is thus `evident,-or example,l that the characteristics thereof Aas) to perumt the W teinperature of the funnel(6 is normally bel o f the Proper amfmnt f duid-- lul'thlmol', 19W. the 'condensation point of the mineral Smc@ the mammal of 'the'cu 11S'P01011S 1t oil\oi` other propellant em loyed and above forms a'rather poor heat con uctor and E tlus A the condensation point of t e water or other aids the maintenance of the lower temperafefrigelfant employed@ .the pressur conditure 0f thslqd' upon its 10W Pressue Side tions prevailing within the system.- Accordl l Ful'thel'mm'ea the HOW 0f the hqul mwaldly ngly the refrigerant 'vapor -iows upwardly tends to counteract the flow of the heat outthrpugh'p-assage 22 whihghas a substantially ,the flue f orbumed nectedto a'condensei'j'i The refrigerant EW 1Sa 1S0 conne. t0 a 1`t1 0n^ 0f the: condensesinthelatter-and iiows downwardlyoiler that is remote` from t e l1 uid surthro,1 h duct 23, whihp--provided:with a -rouldmg the Same and emrly t .e vapor suimb @liquid trap' efijcgimecd tothe e001- er The .cennectioi'i-xaf1 pipe 22 to duct 23 is so arrangedthat fr igerant at the bottom ffof the,lat ter which is vsuicient to balai'i-ce the liquid in the other leg of trap 24 and in the-'coo erfwill not-over` flow into pipe 22 but so thata Acolumn' formed 'a uct which' is notin direct heat'. rzla'tion to the liquid being suppliedierxe v In the accom anying drawings, wherein I the improved iluid'f` levice F1g- 1 ,15' a 111.01902'10-58 (,hgfmmatlc *28W at .pipe rather than flow through theliquid- 0f a' Teflzlge'atmg Systemm'w-h1c mY 5011er. tra. into the cooler. As refrigerant collects feed dem@ 1S employed; and in n @liquid coiumnwithin pipe-23' a portion of thefs'ame returns to the cooler, thus-com: pleting the refrigerant circuit. .v A

-A pipe 30 is connected tothelowe'r end of funnel '6 t9 v`receive 'condensed propellant 1y exfrom the -s'anie and from theupwar ftending pipe 22. This pipe is arranged to propellant tolthe boil-A feedin means employed in conjunction with general type disclosed in my ,copen'ding appli: er fur recirculation,

In. accordance with the priesentinvention, application of LymanJ?.iWhitney; Serial No.' specialliuid'ilow inducingsior- *Em ing means 1927; patented June is provided to permit the' ilui to pumped .,Werdl Pmfereblytif the heting factor horizontai-connctiontoafductesthatis con- ,mi is of t e combustion ty lli 'lumn of liquid relll b the lighten-propellant will overflow into from the pipe 30 at low pressure` to the boiler at a higher pressure. Fig. 2 illustrates more in detail the arrangement of this pumping means which comprises a chamber 31 surrounding the boiler and containing a supply of the liquid received from pipe 30. The boiler 1 preferably is provided with a cuplike Wall portion 33 which is formed of suitable porous material having a multiplicity of capillary passages to permit liquid iow through the same. The edges of the cup member 33 are pressed by springs 34 against a suitable gasket 35 disposed upon one end 36 of the chamber 31, it thus being evident that this wall of the chamber also cooperates with the cup 1 in forming the boiler.

rlhe heating factor 37 preferably is arranged Within the boiler out of direct heat transfer relation to the liquid contained in chamber 31. factor preferably is disposed adjoining the Wall 36 of the chamber which also forms an end of the boiler. lf a heating factor of the combustion type is employed it may be arranged as shown in Fig. 2, wherein the fuel.

supply nozzle 39 is shown projecting through the Wall 36 of the boiler intoa suitable combustion chamber 40. The latter is provided with an intermediate baille 41 separating nozzle 39 from the outlet to the flue 42 through which burned gases are exhausted to the atmosphere, it being evident that the baffle 41 is mounted on the Wall 36 and extends for a substantial portion of the Width of the fireboX, thus causing the hot gases to sweep past all portions of the Wall of the combustion chamber.

The material of the orous cup 33 is so chosen in reference to t e liquid that is to flow through the capillary passages of the same that that liquid will'readily Wet the surfaces of the passages and also have a small and preferably 4a substantially infinitely small angle of contact with these surfaces.

Furthermore the capillary material is so chosen that its largest pores have a diameter suiiiciently small to permit the desired difpressures at opposite to the inner surface of the porous cu l33, I

When ,the material ofthe porous cup has For this purpose the heating Thus, for example, thematerial 45- thus been properly chosen in relation .to the properties of the circulating liquid, the in-` crease of pressure within t e boiler dueto the evaporation of the liquid at the inner side of the porous cu will merely tend to stretch the concave liquid surfaces at the ends ofthe capillary passages without substantial change in the position of the edges of the same that contact with the Walls of the passages, thus permitting the pressure Within the boiler to be substantially higher than that within the pipe 30. When the capillary material and liquid are properly chosen inthis manner, evaporation from the liquid surfaces will at once be replenished.' by additional liquid su plied from the chamber 31 without any ten ency of the liquid surfaces at the ends of the capillary tubes to .retreat under the pressure diiferential imposed thereon. Since the surface tension of the liquid alters the pressure relations under these conditions,

the heat necessary to cause ready vaporiza tion of the same is slightly greater than that which otherwise vwould be required. This increase in the energy that is required to effect the vaporization of he fluid is effective in conjunction with the employed capillary means in pumping the fluida ainst the pressure diiferential and accor ingly 'the vapor is slightly superheated4 as it leaves the capillary passages.

It is evident that the magnitude of the pressure differential against which the Huid may be pumped is determinedby the surface tension of the circulating liquid and theneness of the coarsest pores within the porous solid. The structural arrangement illustrated herein permits the maintenance of a substantially fluid-tight seal between the end of the porous cup and the chamber 31 despite changes in the size of these elements due to thermal expansion as lon as the joint between the gasket 35, whic may be formed, lfor example, of asbestos, and the cup 1 is no greater than the capillary passage, this joint being effective in permitting the satisfactory u operation of the apparatus.

l claim:

1. Fluid feed apparatus ofthe class de scribed, comprising a fiuid ducthaving a low pressure portion and a high pressure portion,

a wall of porous material in the duct providing a multiplicity of capillary passages between the low pressure region and the high pressure region, means for sup lying heat to the high pressure region where y liquid passing through the capillary passages is vaporized, the surface tension of the liquid in the capillary tubes supporting the pressure at to aid vaporization therefrom, said heat con- 1130 ductive liquid having a higher boiling point l than that of the fluid flowing through the f pressure region, said porous material being of such a character that the liquid will have a substantially infinitely small angle of contact with the walls of the capillary passages, means for supplying heat t-o the high pressure region, whereby liquid passing through the capillary passages is vaporized, the surface tension of the liquid in the capillary tubes suppoiting the pressure at the ends of said tubes, and heat conductive liquid in engagement with the porous material at its warm side whereby heat is conducted tothe ends of the capillary passages to aid vaporization therefrom, said heat conductive liquid having a higher boiling point than that of the fluid flowin through the passage.

3. Apparatus o the class described comprising a liquid supply passage, a chamber at the end of the passage, a boiler within the chamber, said boiler having a wall formed of porous material providing a plurality of capillary passages adapted to be wet by the liquidfrom the passage and to have a substantially infinitely small angle of contact with the same, a heating factor disposed out of direct heat transfer relation to thewalls of the chamber and in heat transfer relation to the boiler, and a vapor outlet pipe connected to the boiler, said boiler being partially filled with material which is liquid but substantially non-volatile at the normal boiler temperature.

4. Apparatus of the class described comprising a liquid supply passage, a chamber at the end o chamber, one wall of the boiler being formed.

with the same, a heating factor disposed out of direct heat transfer relation to the walls of the chamber andin heat transferrelation to the boiler, anda vapor outletpipe con- T nected to the boiler, and means `yieldably holding the porous boiler Wall portion against the wall of-the chamber, said vapor the passage, a boiler within the pass into a multiplicity of capillary passages in said material, maintaining a higher temperature at the side of the material toward which thefluid is flowin whereby liquid is evaporated, the pressure eing supported by the surface tension of the liquid and maintaining a heat conductive liquid of high boili ing point in contact with the warm side of the capillary material to augment evaporation of the liquid.

6. A method of feeding fluid from a region of low pressure to a region of higher pressure and concomitantly evaporating the fluid, which comprises feeding the fluid as a liquid to a wall of capillary material`between the two regions, permitting said liquid to pass into a multiplicity of capillary passages with the endof which the liquid makes f a substantially infinitely small angle of conahv portion of the chamber wall, the repipe and the heat supplying means being connected to saidv chamber wall.

5. A method of feeding fluid from a region e of low pressure to a region of higher pres-, sure and concomitantly evaporating the fluid, which comprises feeding the fluid as a liquid to a wall of capillary material between the two regions, permitting said liquid to 

